of ruthenium atoms in a site. If there is preferential interaction of copper with the defects, as can be inferred from the results of the present work, it would be reasonable for copper to have a different effect on the catalytic activity of ruthenium when defects are present. Consequently, the effect of copper on catalytic activity could well be different for a ruthenium powder than it is for a smooth (001) plane of ruthenium.The results of the present investigation clearly demonstrate the value of ultraviolet photoemission spectroscopy of physisorbed xenon as a probe of surfaces of interest in catalysis. Since it is sensitive to localized properties of the surface, it is a powerful probe for the detection of surface heterogeneity. It can therefore make a useful contribution in studies of the structure sensitivity of surface-catalyzed reactions.

No abstract

No abstract

Results of the voltammetric study of benzophenone reduction in dimethylformamide and aqueous media on GCE are presented together with the comparative discussion of the data for mercury and other electrodes available in the literature. The formation and stability of anion radicals and dianions and their reactivity with protonating agents on GCE are similar to those on mercury electrodes. A new surface prewave noticed in aprotic and neutral aqueous solutions on GCE has not so far been reported on any other electrode. All experimental evidences support the view that this prewave is due to the surface protonation by the acidic functional groups on GCE. The surface protonation is found to be a slow time-dependent process requiring 3-4 minutes for completion. The surface concentration evaluated from the faradaic response of the surface process is found to be around 30% or even less if the surface roughness factor is considered,. The importance of this finding to the general concept of surface acidity effects on electrocatalysis is also emphasised.

meío(Tetrakis(benzo-15-crown-5)porphyrin (TCP) and its metal (Mg(II), VivO, Ni(II), Cu(II), Zn(II), and Mn(III)) derivatives form dimers on complexation with K+ ions. The porphyrin ring oxidations of these dimers are found to occur at less anodic potentials relative to the oxidations of the corresponding monomers. The electrochemical redox states of these dimers in conjunction with their electronic absorption and emission features have been used to arrive at the electronic structures. Supermolecular formalism has been proposed to describe the properties of these dimers. EPR data on the oxidized dimer radical cations indicate that the unpaired electron is localized on one of the porphyrin ir systems unlike those found in the reaction-center complex, "special pair" bacteriochlorophyll (BChl) molecules, of the bacterial photosynthetic system.